1. Field of the Invention
The present invention relates to electrically operated fluid control valve units, and more particularly to an electrically operated fluid control valve unit of the type in which a sliding type of fluid control valve is associated with a moving-coil linear motor to control the quantity of fluid flow in proportion to an input electric current applied thereto.
2. Description of the Prior Art
In such conventional fluid control valve units as described above, the moving-coil linear motor includes a bobbin of non-magnetic material axially slidable on a longitudinal tubular core of magnetic material, a permanent magnet for providing magnetic flux in the form of a closed-loop through the tubular core, and a moving-coil wound on the bobbin across the magnetic flux of the magnet for providing a linear force on the bobbin. Thus, the bobbin is displaced in response to an input electric current applied to the moving-coil so that a sliding valve member is linearly moved by the bobbin to control the quantity of fluid flow from an inlet port to an outlet port across the tubular core.
With the above construction, a pair of conductive springs are utilized to connect the moving-coil to an electric control circuit and to bias the bobbin toward its initial position. In use of the control valve unit on a vehicle body structure, it has been experienced that unexpected vibration of the valve unit results in a short circuit of the springs with the valve housing, the tubular core and the like. Consequently, electric current may not be applied to the moving-coil to cause undesired trouble of the valve unit.